Hydrostatic fuel gauge innaccurate

[34cab]

Just finished rebuilding fuel system on my 34 and the NOS fuel gauge registers accurate empty but will only go to just above 1/2 when full. I added another calibration rod to the gauge and this made no difference and there is not room for another calibration rod. Also used indicator fluid from two different vendors still no difference will only read just above 1/2 when tank is full. Anybody run into this before?

Robert